cam chain tensioner

the cam chain tensioner is knackered and the engine has been ticking louder and louder for about a month now.
is it an easy part to change on the 500s model and what pitfalls are there for doing it yourself.
My bike is still slightly leaking engine oil after putting on a brand new engine casing and gasket so i'm temped to book it in with a honda dealer and get them to sort it all.
Also how much is the cam chain tensioner likely to cost.
Bike has 20,000 miles on it.

thanks
James.

The cam-chain tensioner shouldn't take too long....

Easy job as long as you follow the Haynes manual instructions as there are a couple of things you definitely need to get right or major engine damage can occur e.g. retracting the plunger before installing the tensioner.

The tensioner is one of the few craply-designed parts of the bike. I had this same rattling problem which kept coming back after a few thousand miles after I'd installed a new tensioner. I've finally sorted it by following this advice that I found after weeks of trawling through message boards. I did it about 5000 miles back and all is well. When I did the valve clearances recently (my mileage is currently 112,000...) the cam chain was in superb condition and the camshaft sprockets had minimal wear.

Here's the fix:
Try this instead of buying a new CCT
Honda Cam Chain Tensioners, yes they suck big time but there is a $1.50 fix for the later Hondas, F3 and up. If the CCT has a plug (bolt) at the outer end remove it. Buy a 6X1.25X30mm bolt and nut. Thread the nut on the bolt and install the bolt into the hole that the plug was in. Gently (fingertip pressure only) rotate bolt until it makes contact with the piston. Hold bolt with wrench and tighten nut against the CCT case. Your CCT will now be silent. Why does this fix work? The CCT in the Hondas does not have a ratcheting mechanism. It depends on a left handed threaded shaft that is spring loaded. Due to the locking pitch thread design this shaft cannot back up. Sounds good so far. Unfortunatly the shaft stays in one place so long that the constant vibration wears out the shaft or the nut that the shaft rides in. The shaft gets sloppy and does not exert enough pressure on the chain pad so the chain starts to rattle at high rpm. The bolt fix exerts just enough pressure on the threaded shaft that it prevents the shaft from vibrating and backing up thus eliminating the chain noise. Yes you will have to adjust the bolt but so far I have no historical data as to how long the time intervals are in between adjustments. Maybe some of you big milege people can provide the data. Any way, hope it prevents you from buying a new CCT. Latest data, the cheap fix has been working for at least 60K miles in a Honda F4

Hi jchesshyre, has this cct fix been worked in the long term? think i might give it a go before i go buy a new one. 

cheers

Did it work? Well yes and no. When I wrote that message I had 112000 on the clock; I've since reached 150000 and that bike is now in retirement as a donor vehicle because it was using too much oil. (Found one on ebay with 13000 on the clock : ) )

I would describe the 'fix' I listed as more palliative care than a cure. It delays the problem but doesn't cure it, unfortunately. I never bought another tensioner after I did it, but the noise did get gradually worse, just more gradually than it had been before without the fix. Each time it started again I'd adjust the bolt (sometimes screwing it in, sometimes out worked, always being careful not to make it so tight that it affected the tensioner's action), but there came a time when the noise was either there when cold or when warmed up – if I set the bolt so that it was silent when cold it rattled once warmed up, and vice versa. I just got used to it.

So I still don't know what a real cure for the problem is. It is worth pointing out that in my investigations I realised that the sound, contrary to what many people conclude, is not the cam chain rattling, it is the plunger in the tensioner rattling. I guess that as the cam chain wears (mine *looked* pristine when I did the valves as mentioned above but after 112000 it had to have some wear) the tensioner has a more difficult job, or something. It's just frustrating that these engines seem to be able to go on and on, but that the tensioner doesn't seem to have been designed with this in mind.

So I would say try the fix (but as I say being VERY careful not to tighten the bolt so much that it starts winding the tensioner) but ultimately the noise will probably come back, but maybe 20000 miles later instead of 5000.

My new CB is still silent in this regard...I seem to remember my previous one started doing it around 60000, oddly enough literally just after I'd changed from using Castrol GPS to Silkolene Comp4 (explanation?), and at that point it was only around 2-3k rpm. Later on it did it loudly at idle until fully warmed up. It never seemed to affect performance – my CB ran more or less as well at 150000 miles as it had at 24000. And the cam chain always looked new as I said. The only point I noticed was that each time I gave up on a tensioner and changed it for a new one (roughly every 20-30000 miles) there was a shiny, polished area on the end of the plunger that contacts the blade.

Good luck!

The closest I got is http://www.ixxra.com/camchaintensioner/CCTparts.jpg which is off a Blackbird.

In fact read through this whole thread http://www.rrzone.com/forums/showthread.php/3914-Honda-Cam-Chain-Tensioner.

Yes. Will see if I can find it.

jchesshyre wrote:Did it work? Well yes and no.......

Thanks for updating this thread. I was interested in this idea, out of curiosity rather than any concern over the original part. We know it's crap, but it's also fitted to the GL1800 Leadwing......

yeah thanks a lot for the detailed response.

That CCT is fitted to a lot of Honda bikes - and the design is similar to other ones as well.

I *think* the plunger is supposed to keep extending until a particular force is applied (the point at which the chain is optimially tight) and then keep that force applied (by extending further) as the chain wears/lengthens (if it does).

Other threads on other forums that I have read have suggested that the thread you can see in the picture wears at the 'normal' extension point for the CCT which then lets the plunger move slightly, which in turn wears the plunger and this leads to either the plunger moving and making a noise or non-optimal cam-chain tightening, which also makes a noise.

Sorry, not yet. I moved house recently and have yet to sort everything out. If it turns up I'll repost on here.

Beresford wrote:Further to this, has anybody got an old, knackered but complete CCT I could have to take apart and investigate. I'd be happy to pay postage.

PM me your address and I'll post mine out on Monday.

Jchessyre, where did u source a m6 30mm 1.25 bolt?? eBay doesn't seem to have them. I guess the pitch is a bit odd .

I can't remember for sure but I think it was just from B&Q!

...or possibly Halfrauds.

just changed my cct today, due to a rattle from the engine when cold.

old cct was only half extended, so plenty of wear left.

what I did notice was the old one was easier to rewind to allow removal  than the new one was.

I used the key that came with the new one to retract the old one, then had to retract the new one. it seemed to be twice as hard to do.

The spring appears to be a leaf spring, similar to an old clock workings so maybe over time the constant heating /cooling of the cct as the engine is run/shut off weakens the spring so it loses its ability to keep the chain tensioned enough? anyway with the new one in place the rattle has gone.

I have just changed my cct as the chain rattled on a cold engine. when I got it off I saw it had only extended by about half its travel. the chain is much quitter now with the new one on, so I came to the same conclusion.

Maybe someone that repairs clocks can make or source a stronger leafspring

Beresford wrote:

If anyone can source a supply of the appropriate spring steel, it would be possible to repair the cct with a new spring - but is a bit of a fiddle to do this.

The spring is 7mm wide. This ebay item is close.
If it is specified in inches, 5/16 is slightly bigger, but might do. A cct shoulld be repairable for about a fiver, as against £57 to buy.

Crikey! I do like the pragmatic approach. If you can be arsed to do this, I'd doff my hat to you!